PayPal recommends you seek the advice of a professional tax advisor for any questions regarding your Crypto transactions for Gains/Loss, cost basis method, and additional tax filing requirements. 

Total Gain
PayPal reflects your crypto balance position with real-time unrealized gains/losses based on current market conditions. This is shown in dollars and percentages within the Crypto section of your PayPal account.
 
This amount is calculated by the difference between the price you purchased your crypto (your cost basis) and the current average selling price, including the current exchange rate and spread.
 
Cost Basis – Highest In, First Out (HIFO)
Suppose you have sold or transferred any crypto with PayPal. In that case, we'll use the Highest In/First Out (HIFO)* method to identify the disposition of assets with a higher cost basis which could potentially result in a smaller capital gain or a more extensive capital loss. The information provided by PayPal is not intended to be and should not be construed as tax advice. You should consult your tax advisor regarding which cost-basis method is appropriate for your situation.
 
PayPal Documentation
To assist taxpayers with determining their cost basis, PayPal will be providing several documents:

• Transaction Statement: This is a .CSV file that will list the Cryptocurrency transactions along with the date acquired or sold, the quantity of the transaction, fee per transaction, total value, and transaction ID.
• Gains and Losses Statement: This report is a . CSV file that uses the Highest In/First Out (HIFO)* cost basis method, a specific share identification method described in IRS Publication 550. This report is in line with the data fields required on IRS Form 8949 (Sales and Other Dispositions of Capital Assets). PayPal uses the HIFO method to identify the disposition of assets that have a higher cost basis and could potentially result in a smaller capital gain or a more considerable capital loss. The information provided by PayPal is not intended to be and should not be construed as tax advice. You should consult your tax advisor regarding which cost-basis method is appropriate for your situation.

*You won't receive these documents if you don't have any eligible sales.
*The highest cost does not consider the time you held your crypto assets. If your position comprises several tax lots and both long- and short-term holdings, the highest cost may deliver the lowest gains but not the lowest tax rate due to the difference between short- and long-term capital gains tax rates.